Voice over Internet Protocol (VoIP) provides for the conversion of analog audio signals, such as voice signals, into digital data that can be transmitted over a packet-switching network. In contrast, Time-Division Multiplexing (TDM) is a method for transferring data as sub-channels in one communication channel. Whereas a TDM system uses a dedicated path having a fixed number of channels with a constant bandwidth for circuit mode communication, a VoIP system routes the data in packets along different paths.
VoIP communication systems are becoming more prevalent in enterprises, replacing typical TDM telephone systems. In particular, large enterprises with multiple distributed facilities may find huge cost benefits from transporting voice traffic over the existing data network infrastructure through VoIP. In addition to simplified infrastructure, VoIP also presents other advantages over traditional telephone systems, such as the ability to manipulate the voice data and to use a VoIP telephone in most locations having access to the network.
VoIP communication systems also present unique challenges in comparison to traditional telephone systems. VoIP devices generally require more maintenance and monitoring than typical TDM devices. For example, VoIP telephones may need to periodically download data from a central server on the network, such as profile information and software updates, or simply reset themselves to clear an error condition.
In addition, the more sophisticated technology associated with VoIP communication systems presents new challenges with regards to monitoring, diagnosing, and updating the various network elements involved with transmitting VoIP data from one subscriber to another. For example, the voice signals from a subscriber who places a phone call from one location using a VoIP communication system must pass through and be processed by several different elements of the network as they are routed to another subscriber at a different location. Such network elements may include Call Agents, Session Initiation Protocol (SIP) Servers, SIP Clients, Service Brokers, Application Servers, Media Servers, Signaling Gateways, Trunking Gateways, Access Gateways, Access Concentrators, Bandwidth Managers, Edge Routers, Subscriber Gateways, Bridges, Routers, and VoIP communication devices, to name a few. Thus, a problem with the transmission of VoIP signals from one subscriber to another may have several potential causes that should be investigated, depending on how many intervening network elements exist between the two communicating subscribers.
Furthermore, at least some network elements may communicate according to a different signal protocol or format, making the task of obtaining information from each network element in an effort to diagnose a problem or determine the condition of the network even more complicated. For example, File Transfer Protocol (FTP) may be required to obtain call log data from some network elements, Secure Shell (SSH) or Telnet may be required to obtain registration and device status information from other network elements, and still other network elements may require the use of proprietary interfaces to obtain the requisite information.
As a result, the task of monitoring, diagnosing, and updating network elements supporting VoIP communication devices in a large enterprise distributed across multiple sites may involve substantial costs and time investment. Determining which network element to query for which information using which protocol typically requires technically skilled personnel with knowledge on how to access and communicate with the different elements of the network architecture. In addition, each problem that the technicians encounter may require long and thorough investigations to discover the root cause of the problem and the appropriate solution, as multiple network elements must be queried manually for particular data, the obtained data must be arranged appropriately, and the results must be analyzed.